Cinnabarinic Acid-Induced Stanniocalcin 2 Confers Cytoprotection against Alcohol-Induced Liver Injury

We recently identified upregulation of a novel aryl hydrocarbon receptor (AhR) target gene, stanniocalcin 2 (STC2), by an endogenous AhR agonist, cinnabarinic acid (CA). STC2 is a disulfide-linked homodimeric secreted glycoprotein that plays a role in various physiologic processes, including cell metabolism, inflammation, endoplasmic reticulum (ER) and oxidative stress, calcium regulation, cell proliferation, and apoptosis. Our previous studies have confirmed that CA-induced AhR-dependent STC2 expression was able to confer cytoprotection both in vitro and in vivo in response to injury induced by variety of ER/oxidative insults. Here, we used mouse models of chronic and acute ethanol feeding and demonstrated that upregulation of STC2 by CA was critical for cytoprotection. In STC2 knockout mice (STC2-/-), CA failed to protect against both acute as well as chronic-plus-binge ethanol-induced liver injury, whereas re-expression of STC2 in the liver using in vivo gene delivery restored cytoprotection against injury based on measures of apoptosis and serum levels of liver enzymes, underlining STC2's indispensable function in cell survival. In conclusion, the identification of STC2 as an AhR target gene receptive to CA-mediated endogenous AhR signaling and STC2's role in providing cytoprotection against liver injury represents a key finding with potentially significant therapeutic implications. SIGNIFICANCE STATEMENT: We recently identified stanniocalcin 2 (STC2) as a novel aryl hydrocarbon receptor (AhR) target gene regulated by endogenous AhR agonist and tryptophan metabolite, cinnabarinic acid (CA). Here, we showed that CA-induced STC2 expression conferred cytoprotection against apoptosis, steatosis, and liver injury in chronic as well as acute models of ethanol feeding. Therefore, this study will prove instrumental in developing CA as a promising lead compound for future drug development against hepatic diseases.

Polycyclic aromatic hydrocarbons (PAHs) cycling and fates in Galveston Bay, Texas, USA

The cycling and fate of polycyclic aromatic hydrocarbons (PAHs) is not well understood in estuarine systems. It is critical now more than ever given the increased ecosystem pressures on these critical coastal habitats. A budget of PAHs and cycling has been created for Galveston Bay (Texas) in the northwestern Gulf of Mexico, an estuary surrounded by 30-50% of the US capacity of oil refineries and chemical industry. We estimate that approximately 3 to 4 mt per year of pyrogenic PAHs are introduced to Galveston Bay via gaseous exchange from the atmosphere (ca. 2 mt/year) in addition to numerous spills of petrogenic PAHs from oil and gas operations (ca. 1.0 to 1.9 mt/year). PAHs are cycled through and stored in the biota, and ca. 20 to 30% of the total (0.8 to 1.5 mt per year) are estimated to be buried in the sediments. Oysters concentrate PAHs to levels above their surroundings (water and sediments) and contain substantially greater concentrations than other fish catch (shrimp, blue crabs and fin fish). Smaller organisms (infaunal invertebrates, phytoplankton and zooplankton) might also retain a significant fraction of the total, but direct evidence for this is lacking. The amount of PAHs delivered to humans in seafood, based on reported landings, is trivially small compared to the total inputs, sediment accumulation and other possible fates (metabolic remineralization, export in tides, etc.), which remain poorly known. The generally higher concentrations in biota from Galveston Bay compared to other coastal habitats can be attributed to both intermittent spills of gas and oil and the bay's close proximity to high production of pyrogenic PAHs within the urban industrial complex of the city of Houston as well as periodic flood events that transport PAHs from land surfaces to the Bay.

Proximity to Oil Refineries and Risk of Cancer: A Population-Based Analysis

Background

The association between proximity to oil refineries and cancer rate is largely unknown. We sought to compare the rate of cancer (bladder, breast, colon, lung, lymphoma, and prostate) according to proximity to an oil refinery in Texas.

Methods

A total of 6 302 265 persons aged 20 years or older resided within 30 miles of an oil refinery from 2010 to 2014. We used multilevel zero-inflated Poisson regression models to examine the association between proximity to an oil refinery and cancer rate.

Results

We observed that proximity to an oil refinery was associated with a statistically significantly increased risk of incident cancer diagnosis across all cancer types. For example, persons residing within 0-10 (risk ratio [RR] = 1.13, 95% confidence interval [CI] = 1.07 to 1.19) and 11-20 (RR = 1.05, 95% CI = 1.00 to 1.11) miles were statistically significantly more likely to be diagnosed with lymphoma than individuals who lived within 21-30 miles of an oil refinery. We also observed differences in stage of cancer at diagnosis according to proximity to an oil refinery. Moreover, persons residing within 0-10 miles were more likely to be diagnosed with distant metastasis and/or systemic disease than people residing 21-30 miles from an oil refinery. The greatest risk of distant disease was observed in patients diagnosed with bladder cancer living within 0-10 vs 21-30 miles (RR = 1.30, 95% CI = 1.02 to 1.65), respectively.

Conclusions

Proximity to an oil refinery was associated with an increased risk of multiple cancer types. We also observed statistically significantly increased risk of regional and distant/metastatic disease according to proximity to an oil refinery.

Proximity to oil refineries and risk of cancer: A population-based analysis

e13586

Background: Proximity to oil refineries and cancer incidence is largely unknown. We sought to compare the incidence of cancer (bladder, breast, colon, lung, lymphoma, and prostate) according to proximity to an oil refinery in the State of Texas. Methods: A total of 6,302,265 persons aged ≥20 years from January 1, 2001 through December 31, 2014 were identified. We used zero-inflated Poisson regression models to examine the association of proximity to an oil refinery with cancer incidence. Results: We observed that proximity to an oil refinery was associated with a significantly increased risk of incident cancer diagnosis across all cancer types. For example, persons residing within 0-10 (Risk Ratio (RR) 1.16, 95% Confidence Interval (CI) 1.13-1.19) and 11-20 (RR 1.08, 95% CI 1.05-1.11) miles were significantly more likely to be diagnosed with lymphoma than individuals who lived within 21-30 miles from an oil refinery. We also observed differences in stage of cancer at diagnosis according to proximity to an oil refinery. We also found persons residing within 0-10 miles were more likely to be diagnosed with distant metastasis and/or systemic disease than people residing 21-30 miles from an oil refinery. The greatest risk of distant disease was observed in patients diagnosed with bladder cancer living within 0-10 vs. 21-30 miles (RR 1.33, 95% CI 1.06-1.68), respectively. Conclusions: Proximity to an oil refinery was associated with an increased risk of multiple cancer types. We also observed significantly increased risk of regional and distant/metastatic disease according to proximity to an oil refinery.

SAT-652 Increased Fibroblast Growth Factor 21 Protein Expression via in Vivo Delivery of a Liver-Specific Expression Plasmid

Fibroblast growth factor 21 (FGF21) is an important liver-secreted hormone that activates thermogenesis in white and brown fat deposits. In various models of obesity, FGF21 administration consistently facilitates weight loss and improved metabolic function. Several FGF21 variants, which have been engineered to improve protein stability and solubility in solutions containing preservatives, are currently in human clinical trials. In addition, in vivo FGF21 gene therapy using viral vector is being explored as an alternative therapeutic approach. In this study, we present a simpler method of in vivo FGF21 gene therapy, in which liver-specific delivery of an unpackaged plasmid construct expressing an HA-tagged FGF21 protein increases de novo hepatic FGF21 production and secretion in mice. Our data show that FGF21 protein expression can be successfully restored into the livers of FGF21 conditional knockout mice for at least two weeks after a single tail vein injection with the expression plasmid, and that the HA-tagged protein is secreted and readily detectable in serum. In wild-type C57BL6/J mice, in vivo plasmid delivery significantly increased hepatic FGF21 protein 2.3-fold after two weeks, and was associated with reduced body mass and a 14% reduction in fasting serum glucose. In addition, elevated hepatic FGF21 levels correlated with a 27% decrease in the ratio of fat to body mass, visibly smaller subcutaneous and visceral white fat adipocytes, and a 3.3-fold increase in uncoupling protein 1-dependent mitochondrial respiration in the white fat. Together, these data suggest that in vivo plasmid delivery may potentially be an effective strategy for promoting hepatic FGF21 expression in models of obesity. We are currently testing this hypothesis with experiments in high-fat diet-challenged mice.

Using Precision Environmental Health Principles in Risk Evaluation and Communication of the Deepwater Horizon Oil Spill

This article provides a description of the rationale and processes adopted by the Gulf Coast Health Alliance: Health Risks related to the Macondo Spill consortium to evaluate and communicate the risk of exposure to polycyclic aromatic hydrocarbons (PAHs) in seafood over several years following the Deepwater Horizon disaster and subsequent oil spill. We examined gaps in knowledge associated with PAH toxicity following exposure to petrogenic (oil-derived) PAHs by studying the metabolic fate of PAHs and their potential toxicity using sophisticated analytical methods. Using the data generated, we developed a risk communication strategy designed to meet the needs of the stakeholder communities including a consumption guideline calculator, a web-based tool to reconcile seafood consumption with risk of adverse health effects.

Distribution of petrogenic polycyclic aromatic hydrocarbons (PAHs) in seafood following Deepwater Horizon oil spill

A community-based participatory research was utilized to address the coastal community's concern regarding Deepwater Horizon oil contamination of seafood. Therefore, we analyzed polycyclic aromatic hydrocarbons (PAHs), major toxic constituents of crude oil, in the seafood collected from gulf coast (Louisiana, Alabama and Mississippi) during December 2011-February 2014. PAHs were extracted from edible part of shrimp, oysters, and crabs by the QuEChERS/dsPE procedure and analyzed by gas chromatography-mass spectrometry. The total PAHs data were further analyzed using the General Linear Mixed Model procedure of the SAS (Version 9.3, SAS Institute, Inc., Cary, NC) statistical software. Brown shrimp showed statistically significant differences in PAHs levels with respect to time and locations while white shrimp showed differences at various time points. PAHs levels in oyster and crab samples were not statistically different at the Type I error of 0.05. Overall, the PAHs levels are far below FDA levels of concern for human consumption.

Implications of the GC-HARMS Fishermen's Citizen Science Network: Issues Raised, Lessons Learned, and Next Steps for the Network and Citizen Science

This paper is intended to complement our extended documentation and analysis of the activities of the Gulf Coast Health Alliance: Health Risks related to the Macondo Spill project Community Outreach and Dissemination Core entitled, "Building and maintaining a citizen science network with fishermen and fishing communities after the Deepwater Horizon oil disaster using a Community-Based Participatory Research (CBPR) approach." We discuss nuances of CBPR practice, including trust-building, clarification of stakeholder expectations, balancing timelines and agendas, cultural fluency, and the importance of regional history-political-economic context, regulatory practices, and cultural life-ways-in creating social dynamics that overarch and underpin the entire process. We examine the unique role of knowledge-making hybrid structures like the project's Fishermen's citizen science network and compare/contrast this structure with other models of participatory science or deliberation. Finally, we reiterate the importance of environmental health literacy efforts, summarize project outcomes, and offer thoughts on the future roles of collaborative efforts among communities and institutional science in environmental public health.

Building and Maintaining a Citizen Science Network With Fishermen and Fishing Communities Post Deepwater Horizon Oil Disaster Using a CBPR Approach

When the Deepwater Horizon oil rig blew out in 2010, the immediate threats to productive deep water and estuarial fisheries and the region's fishing and energy economies were obvious. Less immediately obvious, but equally unsettling, were risks to human health posed by potential damage to the regional food web. This paper describes grassroots and regional efforts by the Gulf Coast Health Alliance: health risks related to the Macondo Spill Fishermen's Citizen Science Network project. Using a community-based participatory research approach and a citizen science structure, the multiyear project measured exposure to petrogenic polycyclic aromatic hydrocarbons, researched the toxicity of these polycyclic aromatic hydrocarbon compounds, and communicated project findings and seafood consumption guidelines throughout the region (coastal Louisiana, Mississippi, and Alabama). Description/analysis focuses primarily on the process of building a network of working fishermen and developing group environmental health literacy competencies.

COLLABORATING WITH THE COMMUNITY: THE EXTRA-TERRITORIAL TRANSLATIONAL RESEARCH TEAM

The purpose of the present study is to suggest a revision of the team science concept to the more inclusive extra-territorial research team (ETRT). Translational thinking is largely marked by the perception of the team as a thing-like structure at the center of the scientific activity. Collaboration accordingly involves bringing external others (e.g., scientists, community members, and clinicians) into the team through limited or dependent participation. We suggest that a promising and innovative way to see the team is as an idea: a schema for assembling and managing relationships among otherwise disparate individuals with vested interests in the problem at hand. Thus, the ETRT can be seen as a process as well as an object. We provide a case study derived from a qualitative analysis of the impact of the logic of translational science on a team assessment of environmental health following an off-coast oil disaster. The ETRT in question displayed the following principles of constructive relationship management: a high sense of adventure given the quick pace and timeliness given the relevance of the oil spill to all team members; regular meetings in the community to avoid the appearance of academic hegemony; open access by lay as well as institutional scientists; integration of emergency management coordinators into the group; and the languages of public health, environmental pharmacology/toxicology and coastal culture seamlessly interwoven in discussion. The ETRT model is an appropriate strategy for mobilizing and integrating the knowledge and skills needed for comprehensive science and service responses, especially during crisis.

Evaluation of polycyclic aromatic hydrocarbons using analytical methods, toxicology, and risk assessment research: seafood safety after a petroleum spill as an example

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are abundant and widespread environmental chemicals. They are produced naturally and through man-made processes, and they are common in organic media, including petroleum. Several PAHs are toxic, and a subset exhibit carcinogenic activity. PAHs represent a range of chemical structures based on two or more benzene rings and, depending on their source, can exhibit a variety of side modifications resulting from oxygenation, nitrogenation, and alkylation.

OBJECTIVES

Here we discuss the increasing ability of contemporary analytical methods to distinguish not only different chemical structures among PAHs but also their concentrations in environmental media. Using seafood contamination following the Deepwater Horizon accident as an example, we identify issues that are emerging in the PAH risk assessment process because of increasing analytical sensitivity for individual PAHs, and we describe the paucity of toxicological literature for many of these compounds.

DISCUSSION

PAHs, including the large variety of chemically modified or substituted PAHs, are naturally occurring and may constitute health risks if human populations are exposed to hazardous levels. However, toxicity evaluations have not kept pace with modern analytic methods and their increased ability to detect substituted PAHs. Therefore, although it is possible to measure these compounds in seafood and other media, we do not have sufficient information on the potential toxicity of these compounds to incorporate them into human health risk assessments and characterizations.

CONCLUSIONS

Future research efforts should strategically attempt to fill this toxicological knowledge gap so human health risk assessments of PAHs in environmental media or food can be better determined. This is especially important in the aftermath of petroleum spills.

Biomarker discovery for early detection of hepatocellular carcinoma in hepatitis C-infected patients

Chronic hepatic disease damages the liver, and the resulting wound-healing process leads to liver fibrosis and the subsequent development of cirrhosis. The leading cause of hepatic fibrosis and cirrhosis is infection with hepatitis C virus (HCV), and of the patients with HCV-induced cirrhosis, 2% to 5% develop hepatocellular carcinoma (HCC), with a survival rate of 7%. HCC is one of the leading causes of cancer-related death worldwide, and the poor survival rate is largely due to late-stage diagnosis, which makes successful intervention difficult, if not impossible. The lack of sensitive and specific diagnostic tools and the urgent need for early-stage diagnosis prompted us to discover new candidate biomarkers for HCV and HCC. We used aptamer-based fractionation technology to reduce serum complexity, differentially labeled samples (six HCV and six HCC) with fluorescent dyes, and resolved proteins in pairwise two-dimensional difference gel electrophoresis. DeCyder software was used to identify differentially expressed proteins and spots picked, and MALDI-MS/MS was used to determine that ApoA1 was down-regulated by 22% (p < 0.004) in HCC relative to HCV. Differential expression quantified via two-dimensional difference gel electrophoresis was confirmed by means of (18)O/(16)O stable isotope differential labeling with LC-MS/MS zoom scans. Technically independent confirmation was demonstrated by triple quadrupole LC-MS/MS selected reaction monitoring (SRM) assays with three peptides specific to human ApoA1 (DLATVYVDVLK, WQEEMELYR, and VSFLSALEEYTK) using (18)O/(16)O-labeled samples and further verified with AQUA peptides as internal standards for quantification. In 50 patient samples (24 HCV and 26 HCC), all three SRM assays yielded highly similar differential expression of ApoA1 in HCC and HCV patients. These results validated the SRM assays, which were independently confirmed by Western blotting. Thus, ApoA1 is a candidate member of an SRM biomarker panel for early diagnosis, prognosis, and monitoring of HCC. Future multiplexing of SRM assays for other candidate biomarkers is envisioned to develop a biomarker panel for subsequent verification and validation studies.

Role of the aryl hydrocarbon receptor in cell cycle regulation

Traditionally, the aryl hydrocarbon receptor (AHR) is considered to be a ligand-activated receptor and transcription factor responsible for the induction of drug-metabolizing enzymes. Its role in the combinatorial matrix of cell functions was neatly established long before the first report of an AHR cDNA sequence was published. Only recently, other functions of this protein have begun to be recognized. This review addresses novel findings relating to AHR functions that have resulted from experimental approaches markedly outside traditional receptor analyses. Here we examine the aspects of AHR biology relevant to its role in cell cycle regulation, from the activation of mitogen-activated protein kinases to the cross-talk between AHR and the RAS pathway and the functional significance of the interaction between AHR and the retinoblastoma protein. We have attempted to provide the reader with a balanced interpretation of the evidence, highlighting areas of consensus as well as areas still being contested.

Regulation of Cyp1a1 induction by dioxin as a function of cell cycle phase

Analyses of CYP1A1 mRNA were used to monitor the responsiveness of murine hepatoma 1c1c7 and human monocytic U937 cells in different phases of the cell cycle to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Concentrations of TCDD capable of inducing CYP1A1 were not cytostatic to either cell line. Steady-state CYP1A1 mRNA contents were reduced (45-90%) in TCDD-treated cultures arrested in G2/M as a consequence of exposure to microtubule disrupters (Colcemid, estramustine, vinblastine) or the microtubule stabilizer Taxol, relative to TCDD-treated asynchronous 1c1c7 cultures. The accumulation of mRNAs corresponding to Nmo1, another TCDD-inducible gene of the Ah battery, was also reduced in TCDD-treated G2/M cultures. Quantitative reverse transcriptase-polymerase chain reaction analyses of CYP1A1 heterogeneous nuclear RNA (hnRNA) revealed that Cyp1a1 transcription was suppressed in G2/M cells. This suppression reflected neither changes in the relative content of the proteins comprising the aryl hydrocarbon receptor (AHR) complex nor a suppression of AHR activation and translocation to the nucleus. Release of 1c1c7 cultures arrested in G2/M restored TCDD responsiveness. Centrifugal elutriation of TCDD-treated asynchronously growing U937 cells was used to prepare populations of cells in specific phases of the cell cycle. Within 3 h of TCDD exposure late G1/early S phase cells had CYP1A1 mRNA contents approximately 1.4- and 3-fold higher than the contents of asynchronous/early G1 and G2/M cultures, respectively. These studies suggest that the transcriptional activation of members of the Ah battery by TCDD is cell cycle-dependent, and markedly suppressed in G2/M cells.

Progressive Resistance to Apoptosis in a Cell Lineage Model of Human Proliferative Breast Disease

BACKGROUND

Proliferative breast disease (PBD) may increase a woman's risk of developing breast cancer, perhaps by decreasing cellular sensitivity to apoptosis. To determine whether resistance to apoptosis develops during PBD, we investigated apoptosis initiated through the Fas pathway in a series of cell lines that recapitulates the morphologic changes of PBD in nude/beige mice.

METHODS

The series of cell lines used was MCF-10A cells (parental preneoplastic human breast epithelial cells), MCF-10AT cells (transformed with T(24) Ha-ras), and MCF-10ATG3B cells (derivative cells that progress to carcinoma). Fas-mediated apoptosis, induced when a Fas monoclonal antibody bound to and activated the Fas receptor on these cells, was assessed morphologically and by flow cytometry. Levels of proteins involved in Fas-mediated apoptosis and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP), an end product of caspase activation, were determined by immunoblotting. Bcl-2 and Bax heterodimerization was examined by coimmunoprecipitation. All statistical tests were two-sided.

RESULTS

Sensitivity to Fas-mediated apoptosis decreased with the tumorigenic potential of cells: MCF-10A cells were extremely susceptible, MCF-10AT cells were less susceptible, and MCF-10ATG3B cells were resistant. The percentage of apoptotic cells declined, from 24% to 8% to 6%, respectively. All lines produced Fas ligand (FasL) and had comparable levels of Fas receptor, FasL, Fas-associated death-domain protein, and caspases 3 and 6. Levels of caspase 8 were similar in MCF-10A and MCF-10AT cells but about 30% lower in MCF-10ATG3B cells (P>.01 but <.05). Levels of caspase 10 were about 20% lower in MCF-10AT cells (P>.005 but <.01) and about 59% lower in MCF-10ATG3B cells than in MCF-10A cells (P>.01 but <.05). PARP cleavage was detected in MCF-10A and MCF-10AT cells but not in MCF-10ATG3B cells. Levels of Bax, Bid, and Bak proteins were similar in all lines, but levels of Bcl-2 were lower in MCF-10AT and MCF-10ATG3B cells than in MCF-A cells, and Bcl-2-Bax heterodimerization progressively declined in the series.

CONCLUSION

Resistance to Fas-mediated apoptosis appears to develop progressively in the MCF-10AT cell series.

Downregulation of aryl hydrocarbon receptor function and cytochrome P450 1A1 induction by expression of Ha-ras oncogenes

The immortalized human epithelial cell line MCF10A has the phenotypic characteristics of normal breast cells. Exposure of MCF10A cultures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) stimulated the transcriptional activation of cytochrome P450 1A1 (CYP1A1), and CYP1B1, and NAD(P)H:quinone oxidoreductase. Northern blot hybridization and nuclear run-on assays demonstrated that transcriptional activation of these genes was suppressed in stably transfected cultures expressing an Ha-ras oncogene (the MCF10A-NeoT line). Similar suppression did not occur in stably transfected lines carrying the expression vector or a normal c-Ha-ras protooncogene. Western blot analyses and immunofluorescence microscopy demonstrated that the lack of inducibility in MDF10A-NeoT cells reflected neither reductions in aryl hydrocarbon receptor (AHR) and aryl hydrocarbon nuclear translocator protein nor prevention of TCDD-induced AHR translocation to the nucleus. Suppression did correlate with reductions in DNA-AHR complex formation, as analyzed by gel retardation assays of soluble cell extracts treated in vitro with TCDD. The induction of Cyp1a-1 by TCDD was also analyzed in transgenic mice that expressed a v-Ha-ras oncogene exclusively in their keratinocytes. Relative to littermates lacking the transgene, the induction of Cyp1a-1 by TCDD was partially suppressed (about 50%) in the epidermises of v-Ha-ras-positive transgenic mice. However, normal levels of Cyp1a-1 induction occurred in the livers of the same mice. induction of Cyp1a-1 by TCDD was also suppressed (more than 98%) in chemically induced skin papillomas having Ha-ras mutations, relative to uninvolved surrounding skin. These studies suggest that the p21-ras protein controls signal transduction pathways capable of modulating AHR function.